In recent years, wide attention is focused on a capacitive sensor comprising a variable capacitor whose capacitance varies according to the distance between electrodes. The capacitive sensor is applicable to, for example, a pressure sensor. In an application which requires capacitance to be detected with high accuracy, an analog-to-digital converter having a ΔΣ modulator is used.
However, it has been technically difficult to obtain linear input/output characteristics in a conventional ΔΣ modulator, and a ΔΣ modulator having high accuracy has been in great demand in this field.